A pipe joint for connecting a hydraulic apparatus and a piping tube in a pneumatic circuit or the like, that includes a fluid channel formed through a central portion of its main body and in which a tube retention mechanism and a release bush are mounted, is widely known and therefore citing a specific example is unnecessary. The tube retention mechanism is attached to an end portion of the fluid channel, and includes a chuck with a latch claw to be engaged with the outer circumferential surface of a tube inserted therein so as to retain the tube, and the release bush serves to disengage the chuck from the tube upon being pressed into the chuck, thereby allowing the tube to be removed.
In the pipe joint thus configured, the release bush effectively works for the removal of the tube in the case, for example, where the tube has to be removed for modifying the pipe connection or correcting erroneous piping. However, there are sites where the pipe connection is rarely modified after once properly connecting the piping tube to the hydraulic apparatus and, moreover, since the release bush is located at a position where it can be easily accessed, the release bush of the properly connected pipe joint is prone to be accidentally pressed resulting in removal of the properly connected piping tube, during such work as connecting or disconnecting a tube to or from another pipe joint close to the properly connected pipe joint.